title: Monetite and brushite coated magnesium: in vivo and in vitro models for degradation analysis.
abstract: The use of magnesium (Mg) as a biodegradable metallic replacement of permanent orthopaedic materials is a current topic of interest and investigation. The appropriate biocompatibility, elastic modulus and mechanical properties of Mg recommend its suitability for bone fracture fixation. However, the degradation rates of Mg can be rapid and unpredictable resulting in mass hydrogen production and potential loss of mechanical integrity. Thus the application of calcium phosphate coatings has been considered as a means of improving the degradation properties of Mg. Brushite and monetite are utilized and their degradation properties (alongside uncoated Mg controls) are assessed in an in vivo subcutaneous environment and the findings compared to their in vitro degradation behaviour in immersion tests. The current findings suggest monetite coatings have significant degradation protective effects compared to brushite coatings in vivo. Furthermore, it is postulated that an in vitro immersion test may be used as a tentative predictor of in vivo subcutaneous degradation behavior of calcium phosphate coated and uncoated Mg.
authors.affiliation: Department of Anatomy, University of Otago, Dunedin, New Zealand, shaylin.shadanbaz@anatomy.otago.ac.nz.
authors.forename: Shaylin
authors.initials: S
authors.lastname: Shadanbaz
authors.forename: Jemimah
authors.initials: J
authors.lastname: Walker
authors.forename: Tim B F
authors.initials: TB
authors.lastname: Woodfield
authors.forename: Mark P
authors.initials: MP
authors.lastname: Staiger
authors.forename: George J
authors.initials: GJ
authors.lastname: Dias
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry* / Q000493:pharmacokinetics*; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000493:pharmacokinetics*; D003343:Corrosion; D008274:Magnesium / Q000737:chemistry* / Q000493:pharmacokinetics*; D008297:Male; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D051381:Rats; D011917:Rats, Inbred Lew; D013499:Surface Properties
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D008274:Magnesium; C485829:calcium phosphate, dibasic, anhydrous; C494366:calcium phosphate, dibasic, dihydrate